1. Field of the Invention
This invention relates to a movable-type armrest apparatus capable of adjusting the angle of an armrest of a seat in a step-less manner.
2. Description of the Related Art
An armrest on a seat of a vehicle or the like, when not in use, is held in a stored position (closed position) immediately adjacent to a backrest so that it will not become a hindrance.
As shown in FIG. 4, one conventional armrest apparatus includes a shaft lock coil spring 120, and an operating mechanism 150 mounted on an armrest body 110 (see, for example, JP-Y-63-12773). This coil spring 120 is wound tightly on outer peripheral surfaces of the fixed shaft (not shown) fixed to a seat frame 100 side and rotation tube(not shown) (which is provided at the armrest body 110, and is rotatably fitted on the fixed shaft). The coil spring 120 is retained at its one end by the armrest body 110, and a direction of tightening (winding) of this coil spring 120 coincides with a direction of pivotal movement of the armrest body 110 in its opening direction. The operating mechanism 150 comprises an operating member 130, and an interlocking member 140 for transmitting the movement of the operating member 130 to the other end of the shaft lock coil spring 120. By operating the operating member 130, the shaft lock coil spring 120 is driven in an unwinding direction.
FIG. 5 shows an important portion of a structure (see, for example, JP-Y-63-28926) which is an improvement over the above armrest of the JP-Y-63-12773. In this improved structure, when an armrest body 210 is located in a stored position, a hook 230, formed at a free end of a shaft lock coil spring 220, is fitted in a recess 250 formed in a swinging member 240, thereby holding the armrest in this position.
The above prior techniques have the following problems.
Because the locking operation as using the armrest and the lock-canceling operation as adjusting the armrest angle are effected by using the interlock member 140, the operation is cumbersome. And besides, there is a possibility that upon inadvertently touching the interlocking member 140, the locking is accidentally cancelled, thus leading to a malfunction.
On the other hand, in the armrest apparatus of the JP-Y-63-28926, in order to solve the problems with the interlocking member of the JP-Y-63-12773 for effecting the locking operation and the lock-canceling operation, the swinging member 240 is used instead of the interlocking member. The locking operation and the lock-canceling operation are effected by this swinging member 240 provided in the vicinity of a lock mechanism portion. In the armrest-stored position of FIG. 5, a stopper (not shown) is usually provided between an armrest mounting portion (not shown) and the armrest body 210 to prevent a further movement (in a clockwise direction in the drawing) of the armrest from the stored position.
However, when a load, such as the weight of the user's body, tending to further move the armrest from the stored position, is applied thereto, there is a possibility that after the free end hook portion 230 of the shaft lock coil spring 220 is fitted in the recess 250 in the swinging member 240, the armrest is slightly pivotally moved in the clockwise direction because of variations in the component parts or others. As a result, the free end hook 230, the recess portion 250 of the swinging member 240, and that portion of an end member 260, disposed in the vicinity of a stopper wall 270, are liable to be deformed. And besides, the parts of the lock mechanism portion, including the free end hook 230, the swinging member 240 and the end member 260, are complicated in shape, and therefore it is difficult to obtain the required precision of these parts, and therefore this is one cause of the increased cost of the production and the assemblage.